How to defragment your hard drive

What is Disk Defragmenter?

Disk Defragmenter is a tool included in all versions of Windows after Windows 95. It is designed to reorganize the data on your hard drive so that your computer runs more efficiently. You can access it by clicking the Start button, then Programs, then Accessories, then System Tools, then Disk Defragmenter. (There are no built-in defragmenter tools for Mac computers.) If you’re looking for an advanced defragmenter tool for Windows, try Ashampoo Magical Defrag.

I’m a novice. I don’t get it. Can you explain it more clearly?

A hard drive that is badly defragmented is the same thing as a bookstore run by a disorganized proprietor. The books are stocked on the shelves as they come in the door without any rhyme or reason. As he sells them, the proprietor slots in new books in their place because they fit the space, not because they are next to similar books.

This is similar to how a Windows organizes its data on its hard drive. A computer will slot a new piece of data in an empty area of the hard drive, as well. If the file is too big for the slot, it will break it up and put a piece in one slot and another elsewhere.

The next time you ask the computer to open that file, it has to move the hard drive’s heads twice to grab the two pieces of the file, which takes more time. Disk Defragmenter acts as an organized employee would. The employee would sort through all the books and organize them in categories on the shelves so that customers could find them more readily. That’s what Defragmenter (sometimes shortened to simply “Defrag”) does.

Do I have to use the Disk Defragmenter that comes with Windows?

No. There are lots of good third-party defragmenter programs that are much better than the one that comes with Windows. Try this one.

How often should I run Disk Defragmenter?

A hard drive should be defragmented once a month as a good preventative maintenance.

How long does it take?

It depends on the size of your hard drive and the speed of your computer. Typically, it takes a few hours, so it makes sense to set it to run overnight.

Can you provide detailed information on how to defragment my hard drive?

Yes, look at this how-to column: “How to defragment your hard drive”

My defragmenter stalls and refuses to continue. What do I do now?

See our how-to column on “How to fix Windows disk defragmenter if it stalls”.

I have been told that the basic defragmentation procedure doesn’t sort the whole drive. Is there an advanced procedure?

There sure is. Please see: “Hard drive grinding all the time? Stop it!”.

My defragmenter reports that there is not enough memory to continue. Now what do I do?

Ah, we have a solution for that, too. See this column on how to “What to do when defrag says there’s not enough memory”.

My defragmenter still sticks at zero and won’t continue. Nothing else worked—what do I do?

There could be a problem with a bad sector on your hard drive. Run Scandisk first—this is another Windows tool that can be accessed via the Start button, then Programs, then Accessories, then System Tools, then Scandisk.

If you have Windows XP, run Disk Cleanup instead (also found in Accessories > System Tools). If you have Norton Utilities, run Norton Disk Doctor.

Before running Disk Defragmenter, also hit Ctrl-Alt-Del—a box will open, in which you can and should stop any programs that are not mission-critical. One of them could be stopping your computer from proceeding on its defragmentation.

OK, I’ve tried all the tricks and it STILL stalls. Now what?

Get WinTasks 5 Pro, a program that tells you want is running in memory and lets you kill off whatever is getting in the way of allowing Defrag to complete its mission. There’s probably a bunch of hidden programs running that you don’t know are there.

Learn more here.

In addition, look through these articles on the Microsoft Knowledge Base…